1. Field of the Inventions
The field of the invention relates generally to storage containers, and more particularly, to an improved injection molded container that can be used for the transport of dangerous goods and hazardous materials.
2. Background Information
Containers such as buckets and pails are known and used in a variety of shapes and sizes to store various materials. A conventional container is comprised of a cylindrical structure with an interior cavity that is closed at one end. The container may also include a removable cover to secure or close the upper opening of the container. A tubular gasket can also be disposed between the upper bead of the container and the cover to provide an improved seal. A handle may also be attached to the container to help facilitate the carrying and handling of the container.
Despite the broad array of containers that exist, current containers, including plastic containers made through an injection molding process, present numerous shortcomings. These shortcomings become particularly evident when current containers are manufactured for use in transporting dangerous goods and hazardous materials. During transport the containers are often stacked on top of each other several containers high. As a result, it is imperative that each container be able to hold within itself the contents of the materials to be transported and stored as well as support the weight of several containers and their respective contents.
The advent of modern transportation by rail and highway, along with the development of more and more hazardous materials, has increased the need to develop safe containers and packaging to safely transport these materials from one destination to another. Design specifications have become a hallmark to ensure that a company's product can be handled and transported safely and arrive intact at its customer's facility.
While the adoption of specification packaging in the United States ensured a level of safety, other countries did not have to accept the United States' standards. In fact, as other countries adopted their own specifications, it became evident that without international standards, incompatible regulations could hinder the free flow of hazardous materials between countries. A solution to this incompatibility and, in some cases, to the lack of regulations, came from the United Nations' (UN) Committee of Experts on the Transport of Dangerous Goods. This included the adoption of standards that could be used by all nations which based packaging not so much on design as the ability of a given package to pass performance tests. By passing a series of tests, a package design proves itself acceptable for both international and domestic transportation of hazardous materials. For example, a container designed to contain liquids is required to pass a drop test, leakproof test, hydrostatic pressure test and a stacking test. The details of such tests are known or are accessible to those of ordinary skill in the art.
Not surprisingly, the designs of current containers, including plastic containers made through known injection molding techniques, typically attempt to increase the strength and rigidity of the container by adding additional material and thickness to regions of the container that are likely to fail. However, in some cases, this design approach can actually lead to increases in the likelihood of a failure. For example, the junction of two or more wall portions of a container made through injection molding techniques leads to a thick cross section. The thick sections found at the wall junctions of the container often experience a region of increased stress and an increased chance of structural failure when the container is subjected to a performance test or while in actual use. This is due to the fact that during the injection molding process, the regions of increased thickness experience increased heating which, in turn, requires an increased amount of time to cool. In addition, the plastic on the outer portion of the wall junction typically cools faster than the plastic at the inside of the wall junction. This often leads to weakness in the plastic that forms the wall junction.
Therefore, the sections of increased thickness found at the wall junction and other regions of the container can be prone to failure during performance tests or while in actual use. Accordingly, the wall junction and other components found in such containers can actually be strengthened by implementing design features that reduce the amount of material that is used to form the wall junction, while at the same time designing the components of the container to absorb or otherwise withstand the stresses the container is subjected to during performance tests or while in actual use.
Reducing the amount of material that is used to form components of the container can provide other benefits in addition to strengthening the product and its components. For example, reducing the amount of material that is used to form the container can provide a plastic container that is more environmentally friendly. In addition, reducing the amount of material required to produce the container simplifies and speeds up the manufacturing process while reducing the ultimate cost of the container. Such benefits that result from using a reduced amount of material to produce the container cannot be realized, however, without design features that ensure the container can meet the standards required by the United Nations' regulations for dangerous goods and hazardous materials and thereby provide the safe transport of such materials.